One of the major functions of the Center is to provide access to passive silicon substrate probes whose technology is being developed at the University of Michigan under the support of the NIH Neural Prosthesis Program. At this point, only passive probes are available although it is anticipated that the chemical delivery probes and probes with on-chip electronics will one day be available. External investigators may choose passive probes from a catalog of available designs and, once they have shown that they can successfully apply the technology, may design probes customized to their individual application. Technical support in the areas of handling, testing and design is given over the phone or through email. Investigators are also referred to other internal or external investigators with similar interests and/or applications. Since the inception of the Center in May 1994, we have provided at least 130 catalogs and 600 probes to over 150 investigators throughout the U.S. and abroad and have fabricated two mask sets of custom designs. Although distribution of passive probes began in late 1988 under support from the NIH Neural Prosthesis Program, the number of requests for catalogs and probes has grown at a much higher rate since initial funding of the Center. This is most likely due to efforts in the area of information dissemination. Conference presentations by probe users, Center brochures, and press related articles have all resulted in requests for further information by many new potential probe users.